'Standard' vapor website drops 1.5% of requests, even at concurrency of 100!

Your results seem illogical, unless I'm misunderstanding your test setup. If you're using 100,000 concurrent workers, with a two second timeout, then you must have a throughput of at least 50,000 requests per second in order to avoid timeouts. Yet you're reporting only ~8,000 requests/sec with ≤3% timeouts.